vox

A native macOS MCP server that gives Claude a voice.

Built in Swift. No Node.js. No Python. No Electron. Just a single binary.

{
  "mcpServers": {
    "vox": {
      "command": "/path/to/vox"
    }
  }
}

Then just say: listen — and Claude hears you.

---

Tools

Tool	What it does
listen	Activates the mic, waits for you to speak, returns transcript + detected language when silence is detected
speak	Speaks text aloud — ElevenLabs TTS with automatic fallback to macOS system voice

Why Swift + macOS only

• AVFoundation — native mic capture, zero overhead
• SFSpeechRecognizer — Apple on-device speech recognition, works offline, 50+ languages
• NLLanguageRecognizer — automatic language detection per utterance
• AVSpeechSynthesizer — built-in TTS fallback, no API key needed
• Single ~200KB binary. Zero npm install. Zero Python venv.

Requirements

• macOS 13+
• Microphone set as default in System Settings → Sound → Input
• Microphone + Speech Recognition permission for your terminal app
• Optional: ELEVENLABS_API_KEY in ~/.claude/.env for high-quality multilingual TTS

Build & Install

git clone https://github.com/boska/vox
cd vox
swift build -c release --product vox

Add to ~/.claude.json:

{
  "mcpServers": {
    "vox": {
      "command": "/path/to/vox/.build/release/vox"
    }
  }
}

Restart Claude Code. Done.

Voice

Default TTS voice is Hana via ElevenLabs (eleven_multilingual_v2). Supports Chinese, English, Czech, Vietnamese, and 20+ languages in the same voice. Without an ElevenLabs key, falls back to macOS system voice automatically.

How it works

Claude Code
    ↓ JSON-RPC 2.0 over stdio
  vox binary
    ↓                        ↑
AVAudioEngine        AVSpeechSynthesizer
SFSpeechRecognizer       ElevenLabs API
NLLanguageRecognizer

No ports. No sockets. No daemon. Just stdin/stdout.

Troubleshooting

"No speech detected" — speak within ~1s of calling listen, VAD cuts off after 0.8s silence.

No default input device — Mac mini has no built-in mic. Connect USB/Bluetooth mic or iPhone via Continuity Camera, set default in System Settings → Sound → Input.

ElevenLabs silent — add ELEVENLABS_API_KEY=sk-... to ~/.claude/.env, or leave it out to use system voice.